US CO2 Emissions Drop to 20 Year Low 0 Thanos US News8/16/12 6:08:25 pmThursday, August 16, 2012 at 6:08 pm PDT • Views: 900 hosted.ap.org Carbon Dioxide Cautious Global Global Warming Natural Michael Mann Power Plant Operators Surprising Turnaround Greenhouse Gas Lowest Level Dirtier-Burning Coal